1,376 research outputs found

    Analytic lymph node number establishes staging accuracy by occult tumor burden in colorectal cancer.

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    BACKGROUND AND OBJECTIVES: Recurrence in lymph node-negative (pN0) colorectal cancer suggests the presence of undetected occult metastases. Occult tumor burden in nodes estimated by GUCY2C RT-qPCR predicts risk of disease recurrence. This study explored the impact of the number of nodes analyzed by RT-qPCR (analytic) on the prognostic utility of occult tumor burden. METHODS: Lymph nodes (range: 2-159) from 282 prospectively enrolled pN0 colorectal cancer patients, followed for a median of 24 months (range: 2-63), were analyzed by GUCY2C RT-qPCR. Prognostic risk categorization defined using occult tumor burden was the primary outcome measure. Association of prognostic variables and risk category were defined by multivariable polytomous and semi-parametric polytomous logistic regression. RESULTS: Occult tumor burden stratified this pN0 cohort into categories of low (60%; recurrence rate (RR) = 2.3% [95% CI 0.1-4.5%]), intermediate (31%; RR = 33.3% [23.7-44.1%]), and high (9%; RR = 68.0% [46.5-85.1%], P \u3c 0.001) risk of recurrence. Beyond race and T stage, the number of analytic nodes was an independent marker of risk category (P \u3c 0.001). When \u3e12 nodes were analyzed, occult tumor burden almost completely resolved prognostic risk classification of pN0 patients. CONCLUSIONS: The prognostic utility of occult tumor burden assessed by GUCY2C RT-qPCR is dependent on the number of analytic lymph nodes

    Shearlet-based compressed sensing for fast 3D cardiac MR imaging using iterative reweighting

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    High-resolution three-dimensional (3D) cardiovascular magnetic resonance (CMR) is a valuable medical imaging technique, but its widespread application in clinical practice is hampered by long acquisition times. Here we present a novel compressed sensing (CS) reconstruction approach using shearlets as a sparsifying transform allowing for fast 3D CMR (3DShearCS). Shearlets are mathematically optimal for a simplified model of natural images and have been proven to be more efficient than classical systems such as wavelets. Data is acquired with a 3D Radial Phase Encoding (RPE) trajectory and an iterative reweighting scheme is used during image reconstruction to ensure fast convergence and high image quality. In our in-vivo cardiac MRI experiments we show that the proposed method 3DShearCS has lower relative errors and higher structural similarity compared to the other reconstruction techniques especially for high undersampling factors, i.e. short scan times. In this paper, we further show that 3DShearCS provides improved depiction of cardiac anatomy (measured by assessing the sharpness of coronary arteries) and two clinical experts qualitatively analyzed the image quality

    Dark interlayer plasmons in colloidal gold nanoparticle bi- and few-layers

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    We demonstrate the excitation of dark plasmon modes with linearly polarized light at normal incidence in self-assembled layers of gold nanoparticles. Because of field retardation, the incident light field induces plasmonic dipoles that are parallel within each layer but antiparallel between the layers, resulting in a vanishing net dipole moment. Using microabsorbance spectroscopy we measured a pronounced absorbance peak and reflectance dip at 1.5 eV for bi- and trilayers of gold nanoparticles with a diameter of 46 nm and 2 nm interparticle gap size. The excitations were identified as dark interlayer plasmons by finite-difference time-domain simulations. The dark plasmon modes are predicted to evolve into standing waves when further increasing the layer number, which leads to 90% transmittance of the incident light through the nanoparticle film. Our approach is easy to implement and paves the way for large-area coatings with tunable plasmon resonance

    The Structure of Active Merger Remnant NGC 6240 from IRAC Observations

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    NGC 6240 is a rare object in the local universe: an active merger remnant viewed at the point of merging where two active galactic nuclei are visible. We present IRAC data of this object, providing high sensitivity maps of the stellar and PAH distribution in this complicated system. We use photometry to analyze the variation in these distributions with radius and provide an SED in the four IRAC bands: 3.6 microns, 4.5 microns, 5.8 microns and 8.0 microns. We fit the radial profiles of the 3.6 micron band to r^.25 and exponential profiles to evaluate the structure of the remnant. Finally, we compare the IRAC images with multi-wavelength data and examine how outflows in the X-ray, Halpha and CO correlate with 8 micron emission. The results support the general picture of NGC 6240 as a system experiencing a major merger and transitioning from a disk galaxy to a spheroid. The sensitivity of IRAC to low surface brightness mid-infrared features provides detailed information on the extended distributions of stars and dust in this rare system.Comment: Accepted for publication in Ap

    Dark plasmon modes for efficient hot electron generation in multilayers of gold nanoparticles

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    The excitation of dark plasmons, i.e., coupled plasmon modes with a vanishing net dipole, is expected to favor Landau damping over radiative damping. Dark plasmon excitation might, therefore, lead to an increased absorption of energy within gold nanoparticles, resulting in a strong generation of hot electrons compared to the generation via bright plasmons. We performed transient-absorption spectroscopy on gold nanoparticle films to assess the initial electronic temperature before thermalization. We observe a significant increase in the electron–phonon coupling time when dark plasmon modes are excited in these films. The results indicate an efficient energy absorption due to the suppressed radiative decay of dark plasmon modes and a subsequent energy transformation into hot electrons

    Molecular staging individualizing cancer management

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    Although the most important prognostic and predictive marker in colorectal cancer is tumor cells in lymph nodes, ∼30% of patients who are node-negative die from occult metastases. Molecular staging employing specific markers and sensitive detection technologies has emerged as a powerful platform to assess prognosis in node-negative colon cancer. Integrating molecular staging into algorithms that individualize patient management will require validation and the definition of relationships between occult tumor cells, prognosis, and responses to chemotherapy. J. Surg. Oncol. 2012; 105:468-474. © 2012 Wiley Periodicals, Inc. Copyright © 2012 Wiley Periodicals, Inc

    Eignung verschiedener Körnerleguminosen als Vorfrucht für Winterweizen in ökologischen Fruchtfolgen

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    The Aim of this study has been to evaluate in two two-year field trials the pre-crop effect of different grain legumes (e.g. soy bean, peas or lupines) in the same environment and to detect possible effects of grain legumes on the N-supply, the yield potential and the yield structure of the subsequent crop winter wheat. According to different pre-crop yields, a higher but different nitrogen supply for subsequent winter wheat was observed in all N2-fixing pre-crop treatments. In contrast to non-fixings control higher NO3-N contents in soil and higher yields in subsequent winter wheat (up to 24 dt*ha- 1 surplus) were observed

    Ultra-high-field imaging reveals increased whole brain connectivity underpins cognitive strategies that attenuate pain

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    We investigated how the attenuation of pain with cognitive interventions affects brain connectivity using neuroimaging and a whole brain novel analysis approach. While receiving tonic cold pain, 20 healthy participants performed three different pain attenuation strategies during simultaneous collection of functional imaging data at seven tesla. Participants were asked to rate their pain after each trial. We related the trial-by-trial variability of the attenuation performance to the trial-by-trial functional connectivity strength change of brain data. Across all conditions, we found that a higher performance of pain attenuation was predominantly associated with higher functional connectivity. Of note, we observed an association between low pain and high connectivity for regions that belong to brain regions long associated with pain processing, the insular and cingulate cortices. For one of the cognitive strategies (safe place), the performance of pain attenuation was explained by diffusion tensor imaging metrics of increased white matter integrity

    Treatment of primary glioblastoma multiforme with cetuximab, radiotherapy and temozolomide (GERT) – phase I/II trial: study protocol

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    BACKGROUND: The implementation of combined radiochemotherapy (RCHT) with temozolomide (TMZ) has lead to a significant increase in overall survival times in patients with Glioblastoma multiforme (GBM), however, outcome still remains unsatisfactory. The majority of GBMs show an overexpression and/or amplification of the epidermal growth factor receptor (EGFR). Therefore, addition of EGFR-inhibition with cetuximab to the current standard treatment approach with radiotherapy and TMZ seems promising. METHODS/DESIGN: GERT is a one-armed single-center phase I/II trial. In a first step, dose-escalation of TMZ from 50 mg/m(2 )to 75 mg/m(2 )together with radiotherapy and cetuximab will be performed. Should safety be proven, the phase II trial will be initiated with the standard dose of 75 mg/m(2 )of TMZ. Cetuximab will be applied in the standard application dose of 400 mg/m(2 )in week 1, thereafter at a dose of 250 mg/m(2 )weekly. A total of 46 patients will be included into this phase I/II trial. Primary endpoints are feasibility and toxicity, secondary endpoints are overall and progression-free survival. An interim analysis will be performed after inclusion of 15 patients into the main study. Patients' enrolment will be performed over a period of 2 years. The observation time will end 2 years after inclusion of the last patient. DISCUSSION: The goal of this study is to evaluate the safety and efficacy of combined RCHT-immunotherapy with TMZ and cetuximab as first-line treatment for patients with primary GBM

    ABILITY OF COMMERCIALLY AVAILABLE SOYBEAN BRADYRHIZOBIA INOCULANTS FOR COOL GROWING CONDITIONS IN CENTRAL EUROPE

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    In Central Europe the inoculation of soybean (Glycine max (L.) Merr.) with different Bradyrhizobia inoculants has led to unsatisfying nodulation results under low temperature conditions. The aim of this study was to test the capacity of commercially available inoculants under cool growing conditions in Central Europe. In 2011 and 2012 four Bradyrhizobia inoculants were tested on three early soybean varieties in a field trial in Germany. The number of nodules, yield and protein content were assessed. Two years data showed a successful nodulation of Product 4, Product 3 and Product 2 while Product 1 cannot be recommended. Independently of soybean variety, all of the three successful inoculants can be advised regarding grain yield. Protein content and protein yield depend on the combination of inoculants and soybean variety. Over the years Product 4 was the most reliable inoculant
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